The unusual magnetic properties of thin films of Fe1−xCoxOy {0≤x≤1} ferrite solid solutions have been explained through an investigation of their electronic structure. The x-ray absorption near-edge structure (XANES) spectra of the Fe L3-edge and K-edges show that Co replaces Fe3+ in the tetrahedral (Td) sites up to x = 0.34 and octahedral (Oh) sites from 0.39